"After a tough 2014-15 season, both personally and as a team, I took some time to think about my future. It quickly dawned on me that this is exactly where I want to be; being part of a team is not just about winning," Marler said. "I'm a Quin and I love everything about the club. I'm excited for every time I put on the famous quartered shirt and represent this team."

Harlequins director of rugby Conor O'Shea added: "I am staggered that Joe is still only 25. He already has a wealth of experience and when he develops into the player he can be, I have no doubt he will become one of the great loose-head props in world rugby. This is a massive re-signing for us and I'm sure everyone associated with Harlequins will be delighted."